1. Field of the Invention
The invention relates to a labeling machine, more particularly to a labeling machine that is capable of preventing erroneous attachment of labels on containers.
2. Description of the Related Art
Commodities, such as beverage bottles, drug bottles, containers, and packaging boxes, are generally provided with a label to classify products, to indicate usage and other information, to display the trademark or logo of the manufacturer, etc. With the recent advancement in automation, automated attachment of labels to such commodities has taken the place of manual label attachment, and has become quite popular in the industry.
In a conventional label attaching process, a reel of labels is arranged on a reel supporting plate. A leading edge of the reel is drawn via a driving device to a label applicator plate where the labels are applied to containers being advanced by a container conveyer.
Since the sizes of containers vary, the sizes and lengths of the labels attached thereto also vary. Although the conventional labeling machine can perform automatic label attaching, inspection of erroneous attachment of labels on containers is done manually. Particularly, when the bar code printed on a label, which was attached to a container, is incorrect, such an erroneous attachment is hard to inspect according to the appearance of the incorrect bar code. If the incorrect label cannot be inspected, many problems may arise. Furthermore, if a label with a specific bar code and length is attached to the wrong container, such as a drug bottle, such an erroneous attachment may result in dire consequences.
Therefore, the main object of the present invention is to provide a labeling machine capable of preventing erroneous attachment of labels on containers.
According to the present invention, a labeling machine includes a motor-driven container conveying unit, a label applying unit, first and second encoder units, a bar code sensor, a label sensor, a container sensor, and a controller.
The conveying unit has a feed-in end and a take-out end, and is adapted to convey a container from the feed-in end to the take-out end.
The label applying unit is disposed adjacent to the conveying unit between the feed-in and take-out ends, and is operable so as to be adapted to attach a label on the container being conveyed by the conveying unit. The label applying unit includes a reel support plate, a label applicator plate and a motor-driven guide roller unit. The reel support plate is adapted to support a label reel thereon. The label reel includes a backing paper strip and a plurality of the labels releasably and successively adhered on the backing paper strip. Each of the labels has a bar code printed thereon. The label applicator plate is adapted to release one of the labels from the backing paper strip at a label releasing end thereof for application to the container being conveyed by the conveying unit. The guide roller unit is disposed between the reel support plate and the label applicator plate, and is operable so as to feed one end of the label reel on the reel support plate to the label applicator plate.
The first encoder unit is associated with the conveying unit, and is operable so as to generate first distance information to indicate distance advanced by the container due to operation of the conveying unit.
The second encoder unit is associated with the guide roller unit, and is operable so as to generate second distance information to indicate distance advanced by said one end of the label reel during feeding operation of the guide roller unit.
The bar code sensor is disposed adjacent to the reel support plate, and is adapted to sense the bar code on the labels of the label reel and to generate corresponding bar code data.
The label sensor is disposed between the reel support plate and the label applicator plate. The label sensor generates a first signal upon detection of a leading edge of one of the labels on the label reel, and further generates a second signal upon detection of a trailing edge of said one of the labels on the label reel.
The container sensor is disposed adjacent to the conveying unit between the feed-in and take-out ends. The container sensor generates container feature information of the container being conveyed by the conveying unit.
The controller is coupled electrically to the first and second encoder units, the bar code sensor, the label sensor and the container sensor. The controller compares the bar code data from the bar code sensor with predetermined bar code data, and generates an inhibit signal when a mismatch occurs. The controller determines length of one of the labels on the label reel in accordance with the first and second signals from the label sensor and the second distance information from the second encoder unit, compares the determined length with predetermined label length data, and generates the inhibit signal when a mismatch occurs. The controller determines container dimension of the container being conveyed by the conveying unit in accordance with the container feature information from the container sensor and the first distance information from the first encoder unit, compares the determined container dimension with predetermined container dimension, and generates the inhibit signal when a mismatch occurs.